Folicullitis is usually from staph
. Under-skin infection
may be from staph
or strep. Infection usually invades under the skin if there is any (even slight) skin injury, fissure
If it was contact dermatitis (soap, new clothes or washing detergent), there wouldn't be under-skin fluid, I guess.
It may help, if you check in google using "staph scrotum", "celullitis", "staphylococcus groin", "streptococcus groin" and related terms.